feat: scaffold FastAPI backend with ports-and-adapters layout

backend/tests/test_matching.py

@@ -0,0 +1,15 @@
+"""Unit tests for fuzzy grounding decisions."""
+
+from app.domain.matching import title_similarity
+
+
+def test_identical_titles_score_one() -> None:
+    assert title_similarity("Weird Fishes / Arpeggi", "Weird Fishes / Arpeggi") == 1.0
+
+
+def test_remaster_suffix_scores_high() -> None:
+    assert title_similarity("Paranoid Android", "Paranoid Android - Remastered") > 0.7
+
+
+def test_unrelated_titles_score_low() -> None:
+    assert title_similarity("Paranoid Android", "Dancing Queen") < 0.5